Path: utzoo!utgpu!attcan!uunet!lll-winken!ames!mailrus!iuvax!bsu-cs!jdh
From: jdh@bsu-cs.UUCP (John Hiday)
Newsgroups: comp.sys.amiga.tech
Subject: Re: Bug in FFS write-locking?
Message-ID: <5442@bsu-cs.UUCP>
Date: 25 Jan 89 03:26:44 GMT
References: <6028.AA6028@heimat>
Reply-To: jdh@bsu-cs.UUCP (John Hiday)
Organization: Ball State University UCS, Muncie, IN
Lines: 45

In article <6028.AA6028@heimat> sneakers@heimat.UUCP (Dan "Sneakers" Schein) writes:
>In Message <5411@bsu-cs.UUCP>, I write:
>>  [assume no reply from bugs@cbmvax means that nothing made it through]
>  Thats not a good assumption.  The person doing bugs may be busy, may have 
>  not checked the mail yet, or may be trying to reproduce it.

I guess I didn't say how long I waited before posting.  The mail went out
three weeks ago.

> [...]
>  I tried this and your right! Zoo does change the file (as indicated by the
>  date stamp). But I havent been able to get anyting else (besides zoo) to
>  reproduce this.
>
>  Darn this shoots my theory of keeping the Euro-Virus out of my C:
>  directory.

The following program will also demonstrate this:

	#include "stdio.h"
	main()
	{   FILE *output;
	    if (output = fopen("xyz","a")) {
		/* To overwrite add an fseek() here */
		fprintf(output,"This line was appended\n");
	        fclose(output);
		}
	    else {
		printf ("Can't open file\n");
		}
	}

I used Manx 3.6a, but Lattice should work too.

To use it create a garbage file named "xyz" (like Dir >xyz), LOCK the
partition containing "xyz", execute the program and look for the message
at the end of the file.

The Dillon/Drew shell (version 2.07m at least) exhibits the problem when
using >> to redirect output.  That's how I originally discovered it.

-- 
UUCP  : <backbones>!{iuvax,pur-ee}!bsu-cs!jdh                       John Hiday
BITNET: 00JDHIDAY@BSUVAX1.BITNET            Ball State Univ Computing Services
GEnie : JDHIDAY                                               Muncie, IN 47306